Question

Which of the following does not represent a common outcome following introduction of foreign DNA into a bacterial cell?Choose one:
A. If circular, the DNA may persist as a self-replicating genetic element.
B. DNA integrates into the host chromosome.
C. DNA gets degraded by restriction enzymes (endonucleases).
D. Genes may recombine (exchange) with existing host alleles on the chromosome.
E. DNA is exported from the cell by active transport.

Answer 1

Answer:

The correct option is A, since if the DNA enters in a circular form it is called a plasmid, and the plasmids upon entering the bacteria self-replicate outside the genetic structure, which gives the bacteria better survival qualities.

Explanation:

Plasmids are generally circular extrachromosomal DNA molecules that replicate and transmit independently of chromosomal DNA, and are normally present in bacteria, archaea, and sometimes in eukaryotic organisms such as yeast. Its size varies from 3 to 10 kb. The number of plasmids can vary, depending on their type, from a single copy to a few hundred per cell. Plasmid vectors allow cloning of exogenous DNA ligands of up to 4 kb since a larger size than this makes cloning in these vectors difficult. The term plasmid was first introduced by the American molecular biologist Joshua Lederberg in 1952. Plasmids can only coexist as one or more copies in each bacterium, due to cell division they can be lost in one of the secreted bacteria.